Quintero co-founded the Journalists' Club of Valledupar. He was also the local correspondent for "Televista," a news program on the regional channel Telecaribe, and a professor at the National Correspondence University.
On September 29, police arrested two suspects, Jorge Espinal Velásquez and Rodolfo Nelson Rosado Martínez. According to local authorities, both men were identified by witnesses and are believed to be professional assassins.
Many local sources believe Quintero was killed in retaliation for his work as a journalist. They have suggested several possible motives. Quintero had recently been looking into the 1998 murder of Valledupar television journalist Amparo Leonor Jiménez Pallares. According to the attorney general's office, Jiménez was killed in retaliation for a story she broadcast in 1996 about the murder of peasants by a right-wing paramilitary death squad.
Quintero's assassination may also have been prompted by his public denunciation, in July, of an attack on the home of Saída Maestre, a presumed guerrilla sympathizer, in the town of Patillal. Quintero published the article after speaking with Maestre, who was then kidnapped on July 5. Her horribly mutilated body was found sometime later. The right-wing United Self Defense Forces of Colombia (AUC) was linked to Maestre's murder, and many have speculated that Quintero may have signed his own death sentence by publicly denouncing the attack.